1. Technical Field
Example embodiments relate to a security circuit, and more particularly to a security circuit including an electrical fuse circuit.
2. Description of the Related Art
Semiconductor devices implemented with integrated circuits may include an electrical fuse read only memory (ROM). The electrical fuse ROM may operate as storage for an identifier of a semiconductor memory chip, storage for fail address of a redundancy memory cell array, or storage for a security key.
All of fuse memory cells included in the electrical fuse ROM are formed to have the same bit value “0” or to have the same bit value “1” before the fuse memory cells are programmed (i.e., before electrical fuses in the fuse memory cells are blown or open), and then a security key indicated by a user may be programmed into the fuse memory cells during an electrical die sort (EDS) test process or during a packaging process after the semiconductor device on a wafer is fabricated out.
The conventional method of programming a security key may program the security key into an electrical fuse read only memory (ROM) after an integrated circuit is formed on a wafer. Because the security key has to be programmed after fabrication of semiconductor devices, test time and cost may be increased and manufacturing efficiency may be degraded.